This invention relates generally to the packaging of foods and more particularly to a food container and closure which provide a visual indication of unauthorized opening and other tampering. The invention also relates to a method of forming a tamper evident food package.
Food such as cottage cheese, sour cream, yogurt and other dairy products are normally packaged in relatively inexpensive containers formed from injection molded plastic or coated paperboard. It is necessary that the lid fit tightly on the container in order to give the dairy product a prolonged shelf life. The periphery of the lid and the rim of the container are usually formed such that they mechanically interlock in order to hold the lid in place and effectively seal the contents of the container. The lid can simply by lifted off of the container to gain access to the contents, and it can be replaced by pressing it back onto the container to again seal the contents.
This conventional type of food package has been generally satisfactory for the packaging of dairy products, primarily because it permits the contents to be partially removed and the remaining contents to be effectively sealed. However, it is less than satisfactory in other respects. One important drawback is that the lid can be removed and replaced without leaving any visible evidence that the container has been opened. Therefore, it is possible for tampering with the contents to take place on the store shelf without purchasers or store personnel being alerted to the tampering. The deterrence of tampering with foods and other consumable products has taken on increased importance in recent years.
To our knowledge, there has not in the past been available an economical food package suitable for dairy products which is constructed to give a clear visible sign indicating that there has been an unauthorized opening. It is the principal goal of the present invention to provide such a tamper evident food package, along with an economical method of packaging foods therein.
More specifically, it is an important object of the invention to provide a package for food products which visibly indicates whether or not the package has been opened. In accordance with the invention, a skirt on the periphery of the lid is pressed beneath the outwardly rolled container rim to secure the lid in place on the container. The rim or flange portion of the lid is cut to form a weakend tear line interrupted by frangible web portions of the flange. Before the container can be initially opened, at least one of the webs must be broken to permit the skirt to release from the container rim. Consequently, consumers and store personnel can detect whether tampering with the food package has taken place simply by noting whether or not one or more of the webs is broken.
Another object of the invention is to provide a tamper evident closure which can be replaced to tightly seal the container contents following initial opening of the container. After the lid has been initially removed, the skirt can be completely severed from the lid by tearing it along the weakened tear line formed by the cuts. When the lid is thereafter replaced on top of the container, a rib on the periphery of the lid fits closely in a mating groove in the container wall to hold the lid in place on the container. As another important feature of the invention, the detachable strip leaves a projecting tap on the lid to provide a convenient finger grip which facilitates subsequent removal of the lid.
A further object of the invention is to provide a tamper evident food package which retains an attractive, finished appearance following detachment of the removable tear strip. In this respect, it is an important feature of the invention that the ends of the cuts are curved inwardly to avoid the formation of unattractive nibs or other unsightly projections along the tear line.
An additional object of the invention is to provide a tamper evident food package which is constructed simply and economically and which is especially well suited for the packaging of perishable foods such as dairy products in the nature of cottage cheese, sour cream and yogurt.
Yet another object of the invention is to provide a simple and economical method of packaging dairy products and other foods in a tamper evident package.
Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.